This is an example Flask application for a bank. It provides a simplistic REST API for performing basic functions, such as creating an account, checking a balance, and performing deposits and withdrawals.
When asked to implement this exercise, Flask seemed like the natural choice. Django is a fine framework, but seemed a bit heavy on top of my lack of Django experience. It felt too risky to attempt using a framework with which I had little playtime.
I usually start with a Makefile for my repositories because I forget commands
pretty easily after a decade in the industry.
All of my makefiles have a help target and a useful description.
This allows me to be kind to my future self.
I started development with Flask and PDM, as opposed to Poetry or Pipenv. In retrospect, I feel that this was a mistake. PDM is very fast, but there aren't as many resources on using it with distroless containers. While PDM was excellent from the development perspective, I ended up spending a lot of valuable time waiting for containers to build. This was no fault of PDM's, but more how I architected my container to begin with.
When I started, I iterated first with Sqlite. It's an easy-to-use database, and I wanted to test the business logic as rapidly as possible. This was smart! But it ended up being a headache when I needed to transition away from it. My target platform was PostgreSQL. Now that I'm a bit wiser (and have a reference project!), I would have started with pure docker-compose for the development environment.
The implementation of the app itself is not something I'm proud of. I'm a big fan of Clean Architecture and Hexagonal Architecture, but I spent too much time initially fighting with Flask. I find Clean Architecture to be really extensible (though a bit verbose) and testable. Instead, I opted for the middle ground: Flask blueprints. Blueprints allowed me to leave room for scalability in the future, perhaps to toggle bits and pieces of the application on and off at will. This can be a bit dangerous, because I didn't need it just yet, but leaving a path or a signpost to future growth has yet to bite me.
This repository uses a Makefile as its primary orchestrator. These dependencies are required for deployment:
- docker
- docker-compose
- python3
- pdm (obtainable through pip)
These dependencies are optional, but you may find them useful:
- httpie
Once you have obtained the dependencies above, run the following command to set up your development environment:
make init
After that, you are able to hack away at the source code! If you're looking to deploy and test the project, run the following command:
make docker/start
I ended up leveraging a lot of initial structure from this project:
https://github.com/cookiecutter-flask/cookiecutter-flask
Not everything in the repository is how I usually think about things, so some modifications were made. But it helped get me on the right track!